Communication Cite This: Organometallics 2019, 38, 2591−2596
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Click Reaction Driven, Highly Fluorescent Dinuclear Organogold(I) Complex Exhibits a Dual Role: A Rare Au···H Interaction and an Antiproliferative Agent Sanjay K. Verma,† Shagufi Naz Ansari,† Pratibha Kumari,‡ and Shaikh M. Mobin*,†,‡,§ †
Discipline of Chemistry, ‡Discipline of Biosciences and Bio-Medical Engineering, and §Discipline of Metallurgy Engineering and Materials Science, Indian Institute of Technology Indore, Simrol, Khandwa Road, Indore 453552, India
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ABSTRACT: The metal−hydrogen (M···H) bonds in transition elements are well documented. However, the attractive AuI···H bond interaction is rare and significant experimental evidence for it still remains a challenge. Herein, we exhibit a rare example of a C−H···Au interaction in both the solid state and solution by employing a single-crystal X-ray diffraction study and NMR spectroscopy for the novel dinuclear Au(I) complex 1, prepared by a click reaction between organized and strained internal alkynes ((PPh3Au− CC−)2−C6H4) as reacting partners. Furthermore, 1 was found to be highly fluorescent in nature and revealed remarkable antiproliferative properties against skin melanoma cell lines with IC50 values ranging from 3.12 to 8.5 μM.
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ensuing diverse applicability,32 including anticancer activity.33 The noncovalent interactions are the primary driving forces for the construction of exciting supramolecular architectures in gold complexes. In particular, organometallic gold complexes have drawn attention because of their aurophilic properties,34 appealing photophysical properties, and their ability to build a supramolecular array.35 The catalytic chemistry of gold has been strongly stimulated by the availability of 1,2,3-triazoles as convenient ligands in catalysis.36 These triazole-containing heterocyclic ligands have properties that are often congruent to the class of phosphine ligands, and they stabilize highly unusual and previously obscure reactive species.37 Conjugated ethynylated materials and metal-containing acetylide complexes have been investigated for their luminescent, 38 conducting,39 supramolecular,40 and electron/energy transfer properties.41 Gold(I) complexes are an important class of metal complexes due to their luminescent nature, featuring a triplet excited state emission, a relativistic property which allows for the formation of weak Au···Au interactions.42 Recently, there has been tremendous interest in organogold chemistry due to the unique AuI···H bonding interactions in gold(I) complexes which can affect not only solid-state properties such as crystal packing but also chemical reactions and solution-state studies. Au(I) complexes have recently gained attention because of their strong antiproliferative effects due to their antimitochondrial activity, inhibition of the enzyme TrxR, and increasing the formation of reactive oxygen species (ROS) in cells.43,44 Currently non-platinum derivatives
ransition metal complex based M···H interactions have attracted enormous interest in fundamental and applied chemistry, such as in organometallic catalysts.1 In general, the M···H hydrogen bonds involving N−H/O−H donor groups with various transition-metal elements are well documented.2−11 In addition, aurophilic (Au/Au) interactions have been well reported.12 However, the Au···H interaction in gold is still rarely found and has been less explored in gold chemistry and is present either due to the ligand−counterion interaction or crystal packing rather than direct interactions between Au and H atoms.13−17 However, M···H hydrogen bonds in other transition-metal complexes have been well investigated both structurally in the solid state and spectroscopically in the solution state.4−9 However, to the best of our knowledge there exist few reports of experimental evidence of rare C−H···Au “hydrogen bond” interactions both in the solid state and in the solution state.1,18 C−H···Au contacts are commonly complementary in nature and are observed together with stronger noncovalent interactions. The Au···H−C interactions are mainly observed in the phosphine and thione complexes of Au(I), due to the presence of an almost linear geometry around the gold atoms, which influence the coordination site for the formation of gold−hydrogen interactions. Generally, Au···H−C contacts have been observed in the case of intermolecular Au(I) complexes, whereas intramolecular Au···H−C interactions restrict the supramolecular 1D-chain.19−29 Recently, organogold(I) 1,2,3-triazolate complexes have gained much attention because of their fascinating luminescent behavior in order to understand their photophysical and photochemical properties30,31 and mechanisms and their © 2019 American Chemical Society
Received: May 2, 2019 Published: June 17, 2019 2591
DOI: 10.1021/acs.organomet.9b00291 Organometallics 2019, 38, 2591−2596
Communication
Organometallics
Single crystals of the Au(I) complex 1 were obtained by slow evaporation of a dichloromethane solution at room temperature. The single-crystal X-ray diffraction technique has been employed to better understand the influence of substituents on the crystal packing features in the solid-state structure of complex 1. 1 crystallizes in the monoclinic crystal system with space group P21/n (Tables S1 and S2). X-ray diffraction analysis of the crystal confirmed the formation of dinuclear Au(I) complex 1 (Figure 1). The asymmetric unit contains a half
are being intensely studied for their application in cancer chemotherapy.43 To achieve a specific biomolecular target, the metal complex is prepared through a strategic design of the ligand. Herein we report the designed synthesis, characterization, and photophysical properties of the dinuclear Au(I) complex 1, in which the Au(I) units are attached with abnormal mesoionic carbenes of 1,2,3-triazoles. 1 displays a red shift and stronger fluorescence with a high quantum yield probably due to greater perturbation of Au(I) on the π system. Additionally, single-crystal studies of Au(I) complex 1 reveal that it shows rare noncovalent C−H···Au(I) intramolecular interactions. Au(I) complex 1 was synthesized by the reaction of AuCl(PPh3) with 1,4-diethynylbenzene in sodium ethoxide in ethanol solution, resulting in the bis product 1,4-C6H4(C CAu(PPh3))2 in 82% yield (Scheme 1).45 1,4-C6H4(C Scheme 1. Schematic Representation of the Synthesis of 1
Figure 1. Perspective view of 1 showing Au(I)···H(1)−C(1) intramolecular interactions.
formula unit of the Au(I) complex 1. The coordination geometry around the Au(I) atom is found to be linear with the C5−Au1−P1 bond angle measuring about 174.08(3)°, an Au1−C5 bond length of 2.052(11) Å, and Au1−P1 bond length of 2.266(3) Å, falling within the range previously described for gold complexes. The C4−C5−Au1 and Au1−C5−N3 bond angles are 132.80(9) and 123.40(9)°, respectively. The dihedral angle between the NHC plane {N1N2N3C4C5} and the phenyl ring of the benzonitrile unit {C7C8C9C10C11C12} is found to be 76.08° (Figure S8).48 A closer look at the packing features of 1 reveals the presence of rare C−H···Au(I) intramolecular interactions. The intramolecular interaction C(1)−H(1)··· Au(1), at a distance of 2.638(12) Å, involves the donor carbon atom of the phenyl group and the gold(I) acceptor atom (Figure 1). A recent report by Abu Bakar et al.1 has thoroughly detailed C−H···Au interactions in simple diphosphine ligand based hexagold clusters, whereas in our case we have designed the gold(I) complex 1 by activating the challenging internal strained alkyne unit by employing a click reaction between the dimeric {(PPh3Au−CC−)2−C6H4} and 4-(azidomethyl)benzonitrile, which resulted in this rare C−H···Au noncovalent interaction. The bond distances for C−H···Au at 2.638(12) Å (present work) and 2.62 Å (reported) are in agreement. The packing diagram of 1 reveals that the coordination environment of Au(I) is extended further by two different intermolecular C−H···π interactions between the triazole ring and methylene (H6A) proton having distances of 2.748 Å and another intermolecular C−H···π interaction involving the H6B proton of the same methylene group and one of the phenyl ring of the PPh3 group having a distance of 3.130 Å (Table S3). It has been observed that neighboring molecules are linked together through these interactions along the a axis and c axis, yielding a one-dimensional polymeric chain (Figure 2 and Figure S9). After having witnessed the presence of strong C−H···Au(I) intramolecular interactions in the solid state via single-crystal X-ray studies, we broadened the scope by exploring the
CAu(PPh3))2 undergoes a Cu(I)-catalyzed click reaction with 4-(azidomethyl)benzonitrile in the presence of sodium ascorbate and copper sulfate in tert-butyl alcohol and water mixture under reflux conditions for 4−5 h and the resulting product obtained is the dinuclear Au(I) complex 1 (Scheme 1).46,47 1 was characterized by mass spectrometry, 1H and 13C NMR, and a single-crystal X-ray diffraction study. The Au(I) complex 1 is well soluble in dimethylformamide and slightly soluble in dichloromethane and chloroform. The progress of the reaction was monitored by TLC, and the formation of 1 was authenticated by 1H, 13C, and 31P NMR spectroscopy. The Au(I) complex 1 was characterized by FTIR spectroscopy. The band at ∼3100−3000 cm−1 was due to the presence of aromatic C−H stretching vibrations. The 1H NMR spectrum of 1 shows the absence of ethynyl C−H protons of 1,4diethynylbenzene after substitution with gold which was otherwise observed at δ 5.78 ppm for its parent compound. The resonance for the central aryl C−H protons (δ 8.70−8.62 ppm) was shifted significantly downfield in comparison to their analogous resonance (δ 7.37 ppm) in complex 1 (Figures S1− S4). Similarly, the resonance for the carbon atoms of the central phenyl ring was also shifted downfield (δ 131.1−133.1 ppm) in comparison to their corresponding resonances in the free phenyl ring (Figure S5). The resonances for the characteristic carbene carbon atoms were observed at δ 141.8 ppm in the 13C{1H} NMR spectra of complex 1. 1 was also characterized by a 31P NMR spectrum (Figure S6). The LC-MS spectrum of gold(I) complex 1 has a peak at m/z 1358.97, which corresponds to [M]+ (Figure S7) . 2592
DOI: 10.1021/acs.organomet.9b00291 Organometallics 2019, 38, 2591−2596
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Organometallics
and NaNO3 as an acceptor, resulting in the downfield shift of the H-2 proton. Gold(I) complex 1 isolated from the above experiment is found to be stable, as shown in the 1H NMR spectrum recorded after 48 h in the DMSO-d6 solution (Figure S4). Further, the electronic absorption spectral data of the Au(I) complex 1 were recorded in CH2Cl2 solution. The absorption bands of 1 were observed at 220 and 280 nm and were attributed to the π → π* and n → π* transitions for the ligand moiety, occurring due to the heteroaromatic moiety (Figure 4). The fluorescence emission data of the 1 were recorded in Figure 2. Supramolecular C−H···π interaction of 1 along between a and c-axis.
presence of the same C−H···Au(I) interactions in the solution state by employing NMR spectroscopy. The 1H NMR signals of C−H units of the central phenyl ring appear at considerably downfield regions, indicating the presence of hydrogen-bonding interactions in 1 (Figure 3). 31P
Figure 4. UV−visible and fluorescence spectrum of complex 1 at room temperature in 10−5 M CH2Cl2 solution.
CH2Cl2 solution. The emission spectrum of 1 exhibited the highest intensity bands at 327 and 439 nm upon excitation at λex 280 nm (Figure 4). Moreover, the Stokes shifts of Au(I) complex 1 were found to be 47 and 159 nm. The quantum yield of 1 was found to be 0.541. Au(I) complexes are known for their unusual photoluminescence due to the σ-donating property of the anionic carbons, which effectively raises the energy of the d−d states, diminishing their deactivating effect. Thus, the combination of the σ-donating cabon atom of the triazole moiety and Au atom makes it interesting to explore the photoluminescence properties of the Au−triazole unit. The photoluminescence spectrum of 1 reveals the presence of two electronic transitions at 327 and 439 nm attributed to π* → π and π* → n transitions for the ligand moiety (Figure S10) upon excitation at λex 280 nm. The lowest energy absorption for all of the complexes has a metal to ligand charge transfer (MLCT) band which shows an appreciable red shift in some of the unusual complexes. In 1 both the emission spectrum and the photoluminescence spectrum show a similar pattern of the MLCT band, which splits into two partially resolved bands.49 The excellent photophysical properties of 1 prompted us to explore the biological activities of 1. Thus, to determine whether 1 inhibited the proliferation of cancerous cells, (i) a skin melanoma cell line (A375), (ii) a prostate cancer cell lines (DU145), (iii) a cervical cancer cell line (HeLa), and (iv) a breast cancer cell line (MCF-7) were explored. In order to check the cytotoxicity of 1, a normal human embryonic kidney cell line (HEK) was also employed for comparative study.50 The average cell viability decreased with an increase in the concentrations of the compounds. The concentration-dependent inhibitory effects of 1 on the growth of A375, DU145, HeLa, MCF-7, and HEK after 24 h incubation were depicted as the IC50 values 3.12 ± 0.35, 8.5 ± 0.81, 8.5 ± 0.79, 4.68 ± 0.54, and 30 ± 0.23 μM, respectively (Table S4 and Figure 5).
Figure 3. Comparison of 1H NMR spectra of the organogold(I) complex 1 added to a 1.0 mM D2O solution of NaNO3 in DMSO-d6 solution. The arrow indicates the downfield shift of the H-2 proton signals. The other unlabeled signals are due to the P−Ph protons.
NMR spectrum also suggest the presence of a P−Ph moiety in the gold(I) complex 1. After the addition of 5−30 μL (1.0 mM) of NaNO3 solution in D2O, in the DMSO-d6 solution of 1 shows a downfield shift of the H-2 proton (δ 8.62 to δ 10.02 ppm). The Au···H interactions basically involve the H-2 proton of 1 and NaNO3 due to the electronic communication between them. In such interactions C−H behaves as a donor 2593
DOI: 10.1021/acs.organomet.9b00291 Organometallics 2019, 38, 2591−2596
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right (Figure 6), as the cells were treated with 1 for 2 h, specifies an increase in the fluorescence emission intensity,
Figure 6. Flow cytometry analysis (FACS) for reactive oxygen species (ROS) generation by compound 1 performed using a DCFDA probe. The generation of ROS causes a right shift in the histogram (green) in comparison to cells the alone (red) and cells treated with DCFDA (blue). A greater shift suggests a greater production of DCF and thus a higher production of ROS.
resulting from the generation of DCF by the ROS-mediated pathway by oxidation of DCFDA. These reactive oxygen species may cause cell apoptosis. Later, ROS generation was studied by confocal microscopy.52 HeLa cells treated with 1 and the DCFDA probe show strong green fluorescence distributed throughout the cells. A control experiment (without 1) did not show any green fluorescence, suggesting no ROS generation (Figure S12). In conclusion, we have presented here a synthetic strategy for the organometallic dinuclear 1,2,3-triazole-based Au(I) complex 1. 1 was well characterized by various standard spectroscopic techniques such as FTIR, LC-MS, UV−vis, fluorescence, and 1H, 13C, and 31P NMR. 1 has been authenticated by a single-crystal X-ray diffraction study. For the first time a rare and strong intramolecular Au···H−C interaction of 2.638 Å in 1,2,3-triazole-based Au(I) complex was identified by both 1H NMR techniques in the solution state and single-crystal X-ray diffraction studies in the solid state. This novel gold(I) compound reveals remarkable antiproliferative properties against skin melanoma cell lines (A375), prostate cancer cell lines (DU145), cervical cancer cell lines (HeLa), and breast cancer cell lines (MCF-7) with IC50 values ranging from 3.12 to 8.5 μM. Moreover, thorough localization of 1 was evident from confocal imaging with green emission produced by conversion of DCFDA to DCF due to ROS production inside cells. Induction of apoptosis via ROS generation was further evidenced by flow cytometry studies using DCFDA.
Figure 5. Cell viability studies of 1 on cancerous and normal cell lines: (a) skin melanoma cell line (A375) and prostate cancer cell line (DU145); (b) cervical cancer cell line (HeLa), breast cancer cell line (MCF-7), and human embryonic kidney cell line (HEK). These cells were exposed to different concentrations of 1 for 24 h, and then cell viability was measured by an MTT assay.
We have also compared the inhibitory effects of 1 with those of the complex [μ-(1,4-phenylenedi-2,1-ethynediyl)]bis(triphenylphosphine)digold (A) on A375 and HEK cells. It was found that 1 shows more antiproliferative activity in comparison to (PPh3Au−CC−)2−C6H4 (A) on A375 and HEK cells after 24 h incubation having IC50 values of 8.5 ± 0.51 and >30 ± 0.46 mM, respectively (Figure S11). Interestingly, after the click reaction, the introduction of heteroatoms such as 1,2,3-traizole moiety and the nitrile group enhance the inhibitory effects. Further, an in vitro cytotoxicity assay confirmed that the inhibitory effect of 1 on normal cells is significantly lower in comparison to that the selected tumor cell lines. 1 may act as a potential chemotherapeutic agent against cancer. Furthermore, reactive oxygen species (ROS) generated by complex 1 were examined in live HeLa cells by a 2′,7′dichlorofluorescein diacetate (DCFDA) assay. DCFDA is a fluorescence probe which can easily permeate live cells. It measures peroxyl, hydroxyl, and ROS activity within the live cells. Once DCFDA enters inside the cells, it is deacetylated by cellular esterases to a nonfluorescent probe, which is later oxidized by ROS within cells into the highly fluorescent 2′,7′dichlorofluorescein (DCF).51 The amount of DCFDA oxidized to DCF is directly proportional to the generated fluorescence signal. DCF has an emission at 529 nm which can be detected by fluorescence spectroscopy or quantified by flow cytometry analysis. A significant shift in the emission band toward the
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The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.organomet.9b00291. Experimental details, characterization data, crystallographic data, and cell viability studies (PDF) 2594
DOI: 10.1021/acs.organomet.9b00291 Organometallics 2019, 38, 2591−2596
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ing Facilitates Oxidative Addition of the O−H Bond. Chem. Commun. 2002, 0 (22), 2644−2645. (12) Ovens, J. S.; Truong, K. N.; Leznoff, D. B. Structural Organization and Dimensionality at the Hands of Weak Intermolecular Au···Au, Au···X and X···X (X = Cl, Br, I) Interactions. Dalton Trans 2012, 41 (4), 1345−1351. (13) Schmidbaur, H. Proof of Concept for Hydrogen Bonding to Gold, Au···H−X. Angew. Chem., Int. Ed. 2019, 58, 5806−5809. (14) Mishra, V.; Raghuvanshi, A.; Saini, A. K.; Mobin, S. M. Anthracene Derived Dinuclear Gold(I) Diacetylide Complexes: Synthesis, Photophysical Properties and Supramolecular Interactions. J. Organomet. Chem. 2016, 813, 103−109. (15) Koskinen, L.; Jäas̈ keläinen, S.; Kalenius, E.; Hirva, P.; Haukka, M. Role of C−H···Au and Aurophilic Supramolecular Interactions in Gold−Thione Complexes. Cryst. Growth Des. 2014, 14 (4), 1989− 1997. (16) Martínez, A. Do Anionic Gold Clusters Modify Conventional Hydrogen Bonds? The Interaction of Anionic Aun (n = 2−4) with the Adenine−Uracil Base Pair. J. Phys. Chem. A 2009, 113 (6), 1134− 1140. (17) Baukova, T. V.; Kuz’mina, L. G.; Oleinikova, N. A.; Lemenovskii, D. A.; Blumenfel’d, A. L. New Organogold(I) Complexes: Synthesis, Structure, and Dynamic Behavior of the Polynuclear Organogold Diphenylmethane and Diphenylethane Derivatives. J. Organomet. Chem. 1997, 530 (1), 27−38. (18) Rekhroukh, F.; Estévez, L.; Bijani, C.; Miqueu, K.; Amgoune, A.; Bourissou, D. Experimental and Theoretical Evidence for an Agostic Interaction in a Gold(III) Complex. Angew. Chem., Int. Ed. 2016, 55 (10), 3414−3418. (19) Castiñeiras, A.; Fernández-Hermida, N.; Fernández-Rodríguez, R.; García-Santos, I. Supramolecular Architecture in Gold(I) and Gold(III) 2-Pyridineformamide Thiosemicarbazone Complexes by Secondary Interactions: Synthesis, Structures, and Luminescent Properties. Cryst. Growth Des. 2012, 12 (3), 1432−1442. (20) Rodríguez, L.-I.; Roth, T.; Lloret Fillol, J.; Wadepohl, H.; Gade, L. H. The More GoldThe More Enantioselective: Cyclohydroaminations of γ-Allenyl Sulfonamides with Mono-, Bis-, and Trisphospholane Gold(I) Catalysts. Chem. - Eur. J. 2012, 18 (12), 3721−3728. (21) Frik, M.; Jiménez, J.; Gracia, I.; Falvello, L. R.; Abi-Habib, S.; Suriel, K.; Muth, T. R.; Contel, M. Luminescent Di- and Polynuclear Organometallic Gold(I)−Metal (Au2, Au2Agn and Au2Cun) Compounds Containing Bidentate Phosphanes as Active Antimicrobial Agents. Chem. - Eur. J. 2012, 18 (12), 3659−3674. (22) Hejda, M.; Dostál, L.; Jambor, R.; Růzǐ čka, A.; Jirásko, R.; Holeček, J. Synthesis, Structure and Transmetalation Activity of Various C,Y-Chelated Organogold(I) Compounds. Eur. J. Inorg. Chem. 2012, 2012 (15), 2578−02587. (23) Zhou, Y.-P.; Zhang, M.; Li, Y.-H.; Guan, Q.-R.; Wang, F.; Lin, Z.-J.; Lam, C.-K.; Feng, X.-L.; Chao, H.-Y. Mononuclear Gold(I) Acetylide Complexes with Urea Group: Synthesis, Characterization, Photophysics, and Anion Sensing Properties. Inorg. Chem. 2012, 51 (9), 5099−5109. (24) Nuss, H.; Jansen, M. Synthesis and Crystal Structure Determination of Cs([18]Crown-6) Au·8NH3. Z. Naturforsch., B: J. Chem. Sci. 2006, 61 (10), 1205−1208. (25) Nuss, H.; Jansen, M. [Rb([18]Crown-6)(NH3)3]Au·NH3: Gold as Acceptor in N−H···Au− Hydrogen Bonds. Angew. Chem., Int. Ed. 2006, 45 (26), 4369−4371. (26) Dietzel, P. D. C.; Jansen, M. Synthesis and Crystal Structure Determination of Tetramethylammonium Auride. Chem. Commun. 2001, 0 (21), 2208−2209. (27) Schmidbaur, H.; Raubenheimer, H. G.; Dobrzańska, L. The Gold−Hydrogen Bond, Au−H, and the Hydrogen Bond to Gold, Au···H−X. Chem. Soc. Rev. 2014, 43 (1), 345−380. (28) Kilpin, K. J.; Horvath, R.; Jameson, G. B.; Telfer, S. G.; Gordon, K. C.; Crowley, J. D. Pyridyl Gold(I) Alkynyls: A Synthetic, Structural, Spectroscopic, and Computational Study. Organometallics 2010, 29 (23), 6186−6195.
CCDC 1573150 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing
[email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
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AUTHOR INFORMATION
Corresponding Author
*E-mail for S.M.M.:
[email protected]. ORCID
Shaikh M. Mobin: 0000-0003-1940-3822 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS The authors are grateful to the Sophisticated Instrumentation Centre (SIC), IIT Indore, for providing characterization facilities. S.K.V. is grateful to the SERB for providing a National Postdoctoral Fellowship. S.N.A. and P.K. thank the MHRD, New Delhi, for fellowships. S.M.M. thanks the SERBDST (Project No, EMR/2016/001113), New Delhi, Government of India, and IIT Indore for financial support.
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REFERENCES
(1) Bakar, M. A.; Sugiuchi, M.; Iwasaki, M.; Shichibu, Y.; Konishi, K. Hydrogen Bonds to Au Atoms in Coordinated Gold Clusters. Nat. Commun. 2017, 8 (1), 576. (2) Brammer, L. Metals and Hydrogen Bonds. Dalton Trans 2003, 0 (16), 3145−3157. (3) Brammer, L.; Charnock, J. M.; Goggin, P. L.; Goodfellow, R. J.; Koetzle, T. F.; Orpen, A. G. Hydrogen Bonding by Cisplatin Derivative: Evidence for the Formation of N−H···Cl and N−H···Pt Bonds in [NPrn4]2{[PtCl4]·cis-[PtCl2(NH2Me)2]}. J. Chem. Soc., Chem. Commun. 1987, 0 (6), 443−445. (4) Casas, J. M.; Falvello, L. R.; Forniés, J.; Martín, A.; Welch, A. J. Pentafluorophenyl Complexes of Platinum Containing Intramolecular Pt···H Hydrogen Bridging Interactions. Crystal Structures of [NBu4][Pt(C6F5) 3(8-Hydroxyquinaldine)] and [NBu4][Pt(C6F5)3(8Methylquinoline)]. Inorg. Chem. 1996, 35 (21), 6009−6014. (5) Braga, D.; Grepioni, F.; Tedesco, E.; Biradha, K.; Desiraju, G. R. Hydrogen Bonding in Organometallic Crystals. 6. X−H—M Hydrogen Bonds and M—(H−X) Pseudo-Agostic Bonds. Organometallics 1997, 16 (9), 1846−1856. (6) Falvello, L. R. The Hydrogen Bond, Front and Center. Angew. Chem., Int. Ed. 2010, 49 (52), 10045−10047. (7) Chatterjee, S.; Krause, J. A.; Oliver, A. G.; Connick, W. B. Intramolecular NH···Pt Interactions of Platinum(II) Diimine Complexes with Phenyl Ligands. Inorg. Chem. 2010, 49 (21), 9798−9808. (8) Rizzato, S.; Bergès, J.; Mason, S. A.; Albinati, A.; Kozelka, J. Dispersion-Driven Hydrogen Bonding: Predicted Hydrogen Bond between Water and Platinum(II) Identified by Neutron Diffraction. Angew. Chem., Int. Ed. 2010, 49 (41), 7440−7443. (9) Baya, M.; Belío, Ú .; Martín, A. Synthesis, Characterization, And Computational Study of Complexes Containing Pt···H Hydrogen Bonding Interactions. Inorg. Chem. 2014, 53 (1), 189−200. (10) Brammer, L.; McCann, M. C.; Bullock, R. M.; McMullan, R. K.; Sherwood, P. Et3NH+Co(CO)4-: Hydrogen-Bonded Adduct or Simple Ion Pair? Single-Crystal Neutron Diffraction Study at 15 K. Organometallics 1992, 11 (7), 2339−2341. (11) Hascall, T.; Baik, M.-H.; Bridgewater, B. M.; Shin, J. H.; Churchill, D. G.; Friesner, R. A.; Parkin, G. A Non-Classical Hydrogen Bond in the Molybdenum Arene Complex [Η6C6H5C6H3(Ph)OH]Mo(PMe3)3: Evidence That Hydrogen Bond2595
DOI: 10.1021/acs.organomet.9b00291 Organometallics 2019, 38, 2591−2596
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Organometallics (29) Hogarth, G.; Á lvarez-Falcón, M. M. Gold(I) Alkynyl Complexes Derived from Ethynylanilines: Crystal Structure of [Au(CC-4-C6H4NH2){P(3-Tolyl)3}] a Polymer in the Solid State via NH···Au Contacts. Inorg. Chim. Acta 2005, 358 (5), 1386−1392. (30) Hettmanczyk, L.; Spall, S. J. P.; Klenk, S.; van der Meer, M.; Hohloch, S.; Weinstein, J. A.; Sarkar, B. Structural, Electrochemical, and Photochemical Properties of Mono- and Digold(I) Complexes Containing Mesoionic Carbenes. Eur. J. Inorg. Chem. 2017, 2017 (14), 2112−2121. (31) Lo, W. K. C.; Huff, G. S.; Cubanski, J. R.; Kennedy, A. D. W.; McAdam, C. J.; McMorran, D. A.; Gordon, K. C.; Crowley, J. D. Comparison of Inverse and Regular 2-Pyridyl-1,2,3-Triazole “Click” Complexes: Structures, Stability, Electrochemical, and Photophysical Properties. Inorg. Chem. 2015, 54 (4), 1572−1587. (32) Partyka, D. V.; Gao, L.; Teets, T. S.; Updegraff, J. B.; Deligonul, N.; Gray, T. G. Copper-Catalyzed Huisgen [3 + 2] Cycloaddition of Gold(I) Alkynyls with Benzyl Azide. Syntheses, Structures, and Optical Properties. Organometallics 2009, 28 (21), 6171−6182. (33) Zou, T.; Lum, C. T.; Lok, C.-N.; Zhang, J.-J.; Che, C.-M. Chemical Biology of Anticancer Gold(III) and Gold(I) Complexes. Chem. Soc. Rev. 2015, 44 (24), 8786−8801. (34) Koskinen, L.; Jäas̈ keläinen, S.; Kalenius, E.; Hirva, P.; Haukka, M. Role of C−H···Au and Aurophilic Supramolecular Interactions in Gold−Thione Complexes. Cryst. Growth Des. 2014, 14 (4), 1989− 1997. (35) Feng, C.; Gao, G.-Y.; Qu, Z.-R.; Sun, L.-N.; Zhao, H. Exploration of Supramolecular Architecture in Complexes with 1Substituted-1H-[1,2,3]-Triazole-4-Carboxylic Acid: Structural Elucidation and Hirshfeld Surface Analysis. Journal of Inorganic and Organometallic Polymers and Materials 2015, 25 (5), 1233−1238. (36) Wang, W.; Wu, J.; Xia, C.; Li, F. Reusable Ammonium SaltTagged NHC−Cu(I) Complexes: Preparation and Catalytic Application in the Three Component Click Reaction. Green Chem. 2011, 13 (12), 3440−3445. (37) Angermaier, K.; Zeller, E.; Schmidbaur, H. Crystal Structures of Chloro(Trimethylphosphine) Gold(I), Chloro(TriIpropylphosphine)Gold(I) and Bis(Trimethylphosphine) Gold(I) Chloride. J. Organomet. Chem. 1994, 472 (1), 371−376. (38) Bartolomé, C.; Carrasco-Rando, M.; Coco, S.; Cordovilla, C.; Espinet, P.; Martín-Alvarez, J. M. Gold(I)−Carbenes Derived from 4Pyridylisocyanide Complexes: Supramolecular Macrocycles Supported by Hydrogen Bonds, and Luminescent Behavior. Dalton Trans 2007, 0 (45), 5339−5345. (39) Kang, X.; Chong, H.; Zhu, M. Au25(SR)18: The Captain of the Great Nanocluster Ship. Nanoscale 2018, 10 (23), 10758−10834. (40) Yam, V. W.-W.; Cheng, E. C.-C. Highlights on the Recent Advances in Gold Chemistrya Photophysical Perspective. Chem. Soc. Rev. 2008, 37 (9), 1806−1813. (41) Barbieri, A.; Accorsi, G.; Armaroli, N. Luminescent Complexes beyond the Platinum Group: The D10 Avenue. Chem. Commun. 2008, 0 (19), 2185−2193. (42) Chen, J.; Zhang, Z.; Wang, C.; Gao, Z.; Gao, Z.; Wang, F. Cooperative Self-Assembly and Gelation of Organogold(I) Complexes via Hydrogen Bonding and Aurophilic Au···Au Interactions. Chem. Commun. 2017, 53 (84), 11552−11555. (43) Oehninger, L.; Rubbiani, R.; Ott, I. N-Heterocyclic Carbene Metal Complexes in Medicinal Chemistry. Dalton Trans 2013, 42 (10), 3269−3284. (44) Ott, I.; Qian, X.; Xu, Y.; Vlecken, D. H. W.; Marques, I. J.; Kubutat, D.; Will, J.; Sheldrick, W. S.; Jesse, P.; Prokop, A.; et al. A Gold(I) Phosphine Complex Containing a Naphthalimide Ligand Functions as a TrxR Inhibiting Antiproliferative Agent and Angiogenesis Inhibitor. J. Med. Chem. 2009, 52 (3), 763−770. (45) Hurst, S. K.; Cifuentes, M. P.; McDonagh, A. M.; Humphrey, M. G.; Samoc, M.; Luther-Davies, B.; Asselberghs, I.; Persoons, A. Organometallic Complexes for Nonlinear Optics: Part 25. Quadratic and Cubic Hyperpolarizabilities of Some Dipolar and Quadrupolar Gold and Ruthenium Complexes. J. Organomet. Chem. 2002, 642 (1), 259−267.
(46) Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.; Sharpless, K. B. A Stepwise Huisgen Cycloaddition Process: Copper(I)-Catalyzed Regioselective “Ligation” of Azides and Terminal Alkynes. Angew. Chem., Int. Ed. 2002, 41 (14), 2596−2599. (47) Yang, X.; Wang, S.; Ghiviriga, I.; Abboud, K. A.; Veige, A. S. Organogold Oligomers: Exploiting IClick and Aurophilic Cluster Formation to Prepare Solution Stable Au4 Repeating Units. Dalton Trans 2015, 44 (25), 11437−11443. (48) Verma, S. K.; Kumari, P.; Ansari, S. N.; Ansari, M. O.; Deori, D.; Mobin, S. M. A Novel Mesoionic Carbene Based Highly Fluorescent Pd(II) Complex as an Endoplasmic Reticulum Tracker in Live Cells. Dalton Trans 2018, 47 (44), 15646−15650. (49) He, X.; Zhu, N.; Yam, V. W.-W. Synthesis, Characterization, Structure, and Selective Cu2+ Sensing Studies of an Alkynylgold(I) Complex Containing the Dipicolylamine Receptor. Organometallics 2009, 28 (13), 3621−3624. (50) Kumari, P.; Verma, S. K.; Mobin, S. M. Water Soluble TwoPhoton Fluorescent Organic Probes for Long-Term Imaging of Lysosomes in Live Cells and Tumor Spheroids. Chem. Commun. 2018, 54 (5), 539−542. (51) Banerjee, S.; Pant, I.; Khan, I.; Prasad, P.; Hussain, A.; Kondaiah, P.; Chakravarty, A. R. Remarkable Enhancement in Photocytotoxicity and Hydrolytic Stability of Curcumin on Binding to an Oxovanadium(IV) Moiety. Dalton Trans 2015, 44 (9), 4108− 4122. (52) Tang, Q.; Si, W.; Huang, C.; Ding, K.; Huang, W.; Chen, P.; Zhang, Q.; Dong, X. An Aza-BODIPY Photosensitizer for Photoacoustic and Photothermal Imaging Guided Dual Modal Cancer Phototherapy. J. Mater. Chem. B 2017, 5 (8), 1566−1573.
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DOI: 10.1021/acs.organomet.9b00291 Organometallics 2019, 38, 2591−2596
